This invention relates to the art of lithium batteries, and more particularly to a new and improved solid cathode, liquid organic electrolyte lithium battery for delivering high current pulses.
One area of use of the present invention is a battery for operating an implantable cardiac defibrillator, although the principles of the present invention can be variously applied. The purpose of the implantable defibrillator is to prevent sudden death from lethal arrhythmia, and in operation the device continuously monitors the heart rate of the patient, is able to recognize ventricular fibrillation, and subsequently delivers a high energy shock to defibrillate the heart. In order to power this device, implantable high rate batteries have been developed which have the ability to deliver a current pulse and rapidly recover the open circuit voltage.
An example of a battery having high capacity, low self-discharge and good pulsing behavior at all levels is shown and described in U.S. Pat. No. 4,830,940. Manufacture of the cell stack assembly thereof includes, briefly, folding the anode to form a serpentine-like structure, placing individual cathode plates between the folds of the anode structure, and then making electrical connection including welding operations to individual leads of each of the plurality of cathode plates.
It would, therefore, be highly desirable to provide a new and improved high rate battery which reduces the time required to manufacture the cell stack assembly while maintaining the requisite safety and reliability standards in operation.
It is, therefore, a primary object of the present invention to provide a new and improved solid cathode liquid organic electrolyte alkali metal high rate battery and method of making the same.
It is a more particular object of the present invention to provide such a battery and method of making the same wherein the time required to manufacture the cell stack assembly is reduced significantly.
It is a further object of this invention to provide such a battery and method wherein manufacturing time is reduced while at the same time the requisite safety, performance and reliability standards in battery operation are maintained.
The present invention provides a solid cathode liquid organic electrolyte alkali metal high rate cell wherein a combination of an elongated alkali metal anode and elongated solid cathode with separator therebetween is wound to form an anode-cathode subassembly having a jellyroll type configuration and wherein the combination is shaped so that the resulting sub-assembly has a substantially rectangular cross-section, the shaping of the combination being done either simultaneously with or subsequent to the winding thereof. The anode-cathode sub-assembly is placed in a conductive cell casing of prismatic shape having opposed flat faces, a lead of either the anode or cathode is attached to the cell casing depending upon whether case positive or case negative electrical configuration is desired and a lead of the other of the anode or cathode is connected to an electrical connector means extending through the casing in an insulated manner. Liquid electrolyte is introduced to the anode-cathode sub-assembly in the casing whereupon the casing then is sealed closed. The foregoing provides a new and improved prismatic high rate battery which significantly reduces the time required to manufacture the cell stack assembly while maintaining the requisite safety and reliability standards in operation.
The foregoing and additional advantages and characterizing features of the present invention will become clearly apparent upon a reading of the ensuing detailed description together with the included drawing wherein: